1. Field of the Invention
The present invention relates to a cooling system for heat-generating devices; more particularly, to a liquid-cooled assembly which can effectively remove heat from a plurality of electrical heaters, for example, integrated circuits.
2. Description of the Related Art
One example of a conventional liquid-cooled integrated circuit assembly is disclosed in U.S. Pat. No. 4,644,385. As shown in FIG. 1, this assembly includes a wiring substrate 100 and a plurality of integrated circuits 102 mounted on the wiring substrate 100 by solder terminals 104. The integrated circuits 102 are arranged in a series of rows and are supported and electrically interconnected by the wiring substrate 100. A cooling member 106 is attached to each integrated circuit 102. Liquid coolant is provided to a cooling module 108 and is transferred to and from the cooling module 108 and the cooling members 106 via flexible pipes 110 (i.e., bellows). The bellows 110 have sufficient flexibility in the direction normal to the longitudinal axis of the bellows (radial flexibility) to absorb accumulated misalignment tolerances between the cooling members and the cooling module. Heat generated by the integrated circuits 102 is transferred from the integrated circuit to cooling members 106 via a thermal joint and then into the coolant which passes to the various cooling members 106 in series.
One problem associated with this conventional integrated circuit assembly is that the bellows 110 are expensive both from a materials and a labor standpoint. Further, mechanical pressure may be placed on the wiring substrate 100 by the bellows 110. The pressure applied to the wiring substrate 100 by the bellows 110 results in reliability problems associated with stresses in the wiring substrate 100.
In addition, the bellows 110 must be attached to the cooling module 108 to establish a seal between the bellows 110 and the module 108. In a high density packaging environment, accessing the fasteners which are used to attach bellows 110 to the module 108 and to tighten the seal between these elements is very difficult. Further, special tools are required to disconnect the module 108 from the wiring substrate 100.
Further drawbacks of this conventional structure are (1) that the low axial flexibility of the bellows 110 makes it difficult to use a collective assembly or disassembly process, and (2) the failure to protect the solder terminals 104 and the wiring substrate 100 from mechanical stresses during the assembling or disassembling process.